This report is a review of irrigation technologies for smallholders in the context of improving rural livelihoods, especially in regard to the prospects for sub-Saharan Africa. The role of traditional technologies is evaluated and modern water distribution technologies, such as sprinkler and trickle irrigation, are reviewed. Low-cost irrigation systems, including such innovations as the use of treadle pumps and drip-kits are then examined. The most appropriate technology to use varies from place to place depending on a wide range of circumstances. A broad classification has been made based on climate and the traditional agricultural background of the local people, which links technology options to specific places - to agricultural regions and to countries. Some ideas are presented on the direction that might be taken by governments, aid donors, NGOs and the private sector to support future development, with a special emphasis on the need to support a wide range of education and training programmes.
Irrigation has long been seen as an option for improving rural livelihoods by increasing crop production, but massive investments throughout the 1970s and 1980s in sub-Saharan Africa have not borne fruit. Food production targets were not met, development costs were extremely high in relation to returns and there were many technical and management problems that remain unsolved. The decrease in real terms of world cereal prices over the past decade has made it difficult to invest in and maintain irrigated agriculture for basic grain crops.
Much of this criticism was directed at the more formally structured irrigation schemes usually under the control of a government body. Because of this, attention turned in the 1980s to the informal sector- small-scale or smallholder irrigation, which is described as the `bottom-up' or `grass-roots' approach to development. There are many smallholder success stories, particularly where farmers have made the investments themselves.
However, all has not gone smoothly where donors have tried to stimulate development. Donors, funding agencies and national governments, wishing to accelerate the development process, still tend to use a `top down' approach where only lip service is paid to farmer participation. The pace is forced to meet investment targets and market forces have been ignored.
Experience in sub-Saharan Africa has shown that successful smallholders generally use simple technologies and have secure water supplies over which they have full control. The most successful technologies are those that improve existing farming systems rather than those that introduce radically new ideas.
A wide range of well-established traditional technology options is available for use by smallholders including, water harvesting, swamp irrigation, spate irrigation, flood plain irrigation using seasonal water and shallow aquifers, hill irrigation, and groundwater irrigation. There is still, however, considerable room to improve and adapt these traditional technologies to different circumstances.
In recent years there has been a growing interest in new technologies to carry and apply water. These usually cost much more than traditional methods and rely very much on external specialist support from suppliers and distributors. Distribution technologies such as trickle, sprinkle irrigation and piped supplies for the more traditional surface methods, can help farmers to manage their water better as well as reducing wastage. All these technologies have the potential to raise the productivity of water and labour. But they are really only accessible to those farmers who can afford to buy them and who are growing cash crops such as vegetables, fruits and flowers. They are unlikely to be taken up by poor farmers.
This phrase refers to modern technologies that have been developed or modified in some way to bring down their cost. An excellent example is the treadle pump, which was developed specially as a low-cost pump for smallholders and continues to be adapted for particular local needs and markets in the region. Low-cost systems of water conveyance and distribution have not been comprehensively tested and evaluated in the region, with the exception of treadle pumps. The adoption by smallholders of treadle pumps to replace the onerous task of lifting and carrying water and the way in which the support services have developed offers lessons for the promotion of other irrigation technologies.
Low-cost, modern technologies can help smallholders' move from subsistence farming into growing cash crops. Success will be determined more by the capacity of smallholders to take risks and adopt new technologies in situations where services are erratic, costs are high and markets are unpredictable. Factors influencing technology uptake are the existence of a market-driven demand for agricultural produce; a well-designed technology that is both appropriate and affordable for the local farming and manufacturing systems; a local private sector capable of mass production of reliable equipment; effective private sector distribution networks for agricultural inputs and equipment including transport, infrastructure and retailers.
The average rate of irrigation development for the sub-Saharan Africa region (40 countries) over the past 12 years is 43 600 ha/year - an average of 1 150 ha/year for each country. Some countries have average rates of development over 2 000 ha/year (e.g. Tanzania, Nigeria, Niger, Zimbabwe and South Africa).
If the current rate continues over the next 25 years then an extra 1 million ha of irrigation could be brought into production - increasing the total area presently under irrigation by 50 percent. Even at the most optimistic rate, the contribution that irrigation can make to increase food production in the region will be modest unless some of the key constraints are removed.
Speeding up development does not necessarily mean building irrigation schemes faster but building many more of them. An important lesson learned over the past 20 years is that smallholder schemes develop through a slow incremental process of improvement, usually in response to farmer demand. Unfortunately this is at odds with the way in which most donor and government agencies work to specific time schedules.
For irrigation to succeed, experienced and knowledgeable staff will be needed. Labour studies can assess the demand and supply of trained people. Demand is based on the expected growth rates in irrigation and the supply of trained people at all levels is based on the output from both the institutional and in-service training arrangements. Support will undoubtedly be required in order to establish appropriate institutional and in-service training programmes that properly equip people for the jobs they must do to address the fundamental issues related to the improvement and adoption of appropriate irrigation technologies in sub-Saharan Africa.